diff --git a/mock_ares.h b/mock_ares.h
index 0a89de2..95dae94 100644
--- a/mock_ares.h
+++ b/mock_ares.h
@@ -15,7 +15,7 @@
 class MockAres : public Ares {
  public:
   MockAres();
-  virtual ~MockAres();
+  ~MockAres() override;
 
   MOCK_METHOD1(Destroy, void(ares_channel channel));
   MOCK_METHOD5(GetHostByName, void(ares_channel channel,